IP address conflict

[Tefler]

I have a network of 8 computers to look after, all of which connect to the internet through one of them. There is unrestricted access to the machines for lots of people, so I suspect somebody who 'knows' about computers may have fiddled.

When I booted up a couple of days ago on the master computer, I got the error message 'IP Address Conflict'. One of the other computers would not, then, connect to the Internet: 'Cannot find server. Page cannot be displayed.' I went to 'My Network Places' and found that the 'bad' computer couldn't see any other computers on the network. Nor could the master computer see it, although it was happy with the others.

Since then, a second computer has stopped connecting to the Internet. This time, although it can't see any of the others, the master computer acknowledges it.

Any advice on:

1. How to solve this problem?
   
2. How to stop people from doing this in the future?

[u-chappy]

With all due repect Tefler, you need to do a little reading up if you can't resolve an IP address conflict and your lookin' after an 8 PC network and there are to many varaibles to give you specific advice but I'll try.

I'll have to assume Windows XP.
I'll have to assume Internet connection sharing.
I'll have to assume DHCP.

All IP's must be unique so one possible cause could be that someone's set a static IP on a machine.

Check DHCP.
Check IP's on each machine.

If unsure, turn off all PC's and boot one by one fully starting with main PC that's doing internet sharing. On boot, check and note IP. Monitor already booted PC's for IP conflicts. If you get one then it's the last PC you booted that's causing the issue.

Don't allow unrestricted access.

Create basic user accounts (if on XP or 2000). If on anything older - upgrade.

Hope that helps - best I can do on info given buddy.

[Tefler]

Yep, somebody had set a static IP on one of the machines.

Yes, I probably do need to do some reading up u-chappy. Looking after the machines wasn't my choice, but got landed on me and I'm learning on the job. People on Answerbank have been very polite and helpful in the past about the difficulties I've had and, so far, there's not been a problem that I've not been able to solve with the kind help of people on here.

Isn't it strange how 'with all due respect' can read like 'with no respect at all'?